Dispersant composition

ABSTRACT

A composition comprising particulate solid (typically a pigment or filler), an organic medium (typically the organic medium may be a plastics material or an organic liquid) and a polyacrylic-acid-containing copolymer.

FIELD OF INVENTION

The invention relates to a dispersant composition and more specificallya dispersant for a composition containing a particulate solid, anorganic medium, and a polyacrylic-acid containing copolymer. Theinvention further relates to novel compounds, and the use of thepolyacrylic-acid-containing copolymer as a dispersant.

BACKGROUND OF THE INVENTION

Mineral fillers such as calcium carbonate are commonly added to aplastic material (such as unsaturated polyester resins) to providereinforcement, increase hardness and to lower overall formulation cost.Other mineral fillers such as alumina trihydrate, which endothermicallydecompose upon heating to liberate water, are known to have a flameretardant effect in plastic materials such as unsaturated polyestercomposites. However, adding a significant amount of filler the overallviscosity of the system generally increases. Dispersing agents arecommonly used to wet out the dry filler during mixing, reduce theviscosity and make the formulation more workable. Phosphate esters arehighly effective dispersing agents but they cannot be used in hand- andspray-lay-up applications due to interference with the curing mechanism.

Such reinforced plastic material as referred above, comprising a plasticmaterial, filler and a dispersant are used in the industry as materialfor yacht interiors, boat hulls, wind turbines, train interiors and thelike. The required plastic/filler/dispersant composition is generallyplaced into a mould and set. The addition of more filler to thecomposition with respect to the plastic material, cheapens the cost.However, if too much filler is added to the mix, the composition becomestoo viscous and harder to work. Dispersants are also used for paints,inks and pigments.

Fillers not only reinforce the plastic for added strength, they can alsooffer other advantages. For example, a known filler, aluminiumtrihydrate is commonly used as a fire retardant filler. Upon heating ofthe plastic containing the fire retardant filler, the aluminiumtrihydrate decomposes to release water, therefore preventing thematerial from catching fire.

A number of references disclose dispersants for media such as plasticsare summarised below.

U.S. Pat. No. 5,300,255 discloses dispersants containing a polyesterderived from a hydroxycarboxylic acid with not more than 8 carbon atomsreacted with phosphorus pentoxide or sulphuric acid. The dispersants areuseful in non-polar media, such as aromatic solvents and plastics.

U.S. Pat. No. 5,130,463 discloses dispersants containing apolyether/polyester derived from ε-caprolactone reacted withpolyphosphoric acid.

U.S. Pat. No. 6,051,627 discloses dispersants including a polyetherderived from ethylene oxide and propylene oxide reacted withpolyphosphoric acid.

U.S. Pat. No. 4,281,071 discloses the use of an organo-phosphite forviscosity reduction of filled unsaturated polyester resin compositions.

Non-phosphate dispersants are disclosed in U.S. Pat. No. 3,332,793. U.S.Pat. No. 3,332,793 discloses suspending agents based upon carboxylicacid-terminated polyether/polyester chains subsequently reacted with apolyamine.

A number of documents disclose methoxy polyethylene glycol esters ofpolyacrylic acids and their use as dispersants.

EP 2 065 403 A discloses a process for making methoxy polyethyleneglycol esters of polyacrylic acid, and their salts, as dispersants forgypsum, cement, and pigments in aqueous systems.

EP 1 061 089 A discloses methoxy polyethyleneglycol esters ofpolyacrylic acid, modified with organic amines, as cementsuper-plasticisers.

U.S. Pat. No. 5,840,114 discloses a methoxy polyethyleneglycol ester andmethoxy polyethyleneglycol amide of a polycarboxylic acid prepared bydirect esterification/amidation.

U.S. Pat. No. 5,476,885 discloses methoxy polyethyleneglycol esters ofpoly(meth)acrylic acids prepared from the reaction of the methoxypolyethyleneglycol with (meth)acrylic acid.

German Patent DE 3 325 738 discloses products made by the directesterification of polyacrylic acid with C₁₆₋₁₈ alcohol ethoxylates.

WO 2010/127809 appears to relate to comb polymers where some of the comb“teeth” are polyesters prepared from diol and diacid constituents, inaddition to polyether grafted chains.

EP 2208761 appears to refer to acrylic comb polymers directly reactedonto the surface of pigment or filler particles.

EP 2065403 appears to refer to similar grafted co-polymers, but alsoappear to stipulate a phosphorus-containing group in the structure.

There are two commonly known processes for polymerizing plasticsmaterial. The first method is that of heat curing. Heat curing involvesthe heating of the reaction mixture in order to initiate polymerization.In the heat cure process, phosphates are added as dispersants as theyare highly efficient at lowering the viscosity of a plasticmaterial/filler mix.

The second method is that of curing at an ambient temperature. At anambient temperature, the reaction is initiated by metal initiators,commonly cobalt complex activators.

Dispersants are commonly used in unsaturated polyester composites toincorporate high levels of mineral fillers effectively whilstmaintaining a workable viscosity.

In ambient temperature cure systems, the cross-linking reaction, using aperoxide radical source, is initiated by the use of cobalt complexactivators. The cross linking reaction involves the linking ofunsaturated polyesters to form chain polymers through polymerization. Itis before this stage of the process that fillers and dispersants areadded to the mixture.

The use of cobalt as a mineral catalyst is commonly used, however, otherpromoters are also used such as copper, manganese, zinc, zirconium andiron, when a cobalt free system is required. Such promoters can be usedin conjunction with dimethylaniline, which has an effect of shorteningthe cure time of the polymerization process.

However, in ambient cure processes, phosphates cannot be used asdispersants.

Strongly acidic dispersants, such as phosphate esters, bind to suchcobalt initiators and delay or prevent the cross-linking reaction fromtaking place.

Consequently, there is interest in alternative chemistries to provideeffective dispersants in such systems which will not interfere incross-linking reactions.

GB 887 241 discloses a range of dispersing agents designed for use inambient-cure composites. These products, based upon polyether-polyesterchains as a salt with a polyamine, have a good effect on wettingfillers, with only a minimal effect on cure retardation. However, thedispersants disclosed are inefficient as they comprise a single anchorgroup in the chain, therefore a high quantity of dispersant is needed toreduce the viscosity of a filler/plastic material mix.

Mineral fillers such as calcium carbonate are commonly added tounsaturated polyester resins to provide reinforcement, increase hardnessand to lower overall formulation cost. Other mineral fillers such asalumina trihydrate, which endothermically decompose upon heating toliberate water, have a flame retardant effect when used as filler inunsaturated polyester composites. The adverse effect of adding asignificant amount of filler is that the overall viscosity of the systemincreases. Dispersing agents are commonly used to wet out the dry fillerduring mixing, reduce this viscosity and make the formulation moreworkable. Phosphate esters are highly effective dispersing agents in aheat cure process but they cannot be used in hand and spray-lay-upapplications due to interference with the curing mechanism.

During a cure process, unsaturated polyesters, which are supplied as asolution in styrene or other reactive monomer, are cured by a radicalmechanism, initiated by an organic peroxide such as methyl ethyl ketoneperoxide. The radicals thus created crosslink the double bonds in thepolyester resin with the double bonds in the styrene diluent, forming arigid 3-dimensional network. The starting point of the reaction is thedecomposition of the organic peroxide, which can be initiated using aheated mould (heat-cure) or by using an organo-cobalt compound dissolvedin the resin (ambient or cold cure).

Many dispersing agents for use in these systems are based upon phosphateesters. Phosphate groups bind tightly to basic filler surfaces, thusgiving effective wetting and viscosity reduction. They also, however,bind tightly to the cobalt compound, thus inhibiting the breakdown ofperoxide and retarding the cure of the composite. Consequently,phosphated dispersants cannot be used in metal activated ambient curedsystems.

None of the known dispersants, as disclosed herein, are able to controlthe rate of curing and furthermore, there is a need for a dispersantthat can be used in an ambient cure system and have a high dispersantactivity with respect to lowering the viscosity of a plastics/filler mixtherefore, enabling an increase in filler to be added to a plasticsmaterial, therefore lowering manufacturing costs.

SUMMARY OF THE INVENTION

The inventors of this invention have discovered that the compositionsdisclosed herein are capable of at least one of increasing a particulatesolid load, provide enhanced curing performance, form improveddispersions and reduced viscosity.

The dispersants as disclosed below, have a high dispersant activity,therefore allows an increase in filler that can be added to a plasticsmix due to an efficient reduction in viscosity of the mix. Furthermore,the dispersants below increase the homogeneity of a plastic/filler mixproviding for a higher grade finished plastic product. The enhanceddispersant capabilities are further advantageous as the workability ofthe plastic/filler mix is improved, therefore making the plastic easierto manufacture.

The dispersants, as outlined below, can be used in both heat cure andambient cure systems, however, are particularly suitable for ambientcure systems as they do not interfere with the mineral activators (i.e.,cobalt activators) and therefore do not inhibit the ambient cureprocess.

The mole percent of repeat units represented by formula (1) below may bedetermined by a number of techniques well known to a person skilled inthe art. The techniques include NMR, or by measurement of acid value bytitration.

In one embodiment, the invention provides a polyacrylic-acid-containinggraft copolymer (the copolymer may be random, blocky, or have randomblocks). The general formula of the polyacrylic-acid containing graftcopolymer (dispersant) is as follows:—[CH₂—C(A)(R₁)]_(j)—[CH₂—C(R₁)(R₂)]_(k)—[CH(A)-C(R₁)(A)]_(l)—  Formula 1j is formed from a polyacrylic acid monomer, k is formed from a dodeceneor vinyl monomer of a different chain length and l is formed from amaleic acid monomer.whereinR₁ is H or —CH₃R₂ is H or a C₁-C₁₆ alkyl, preferably C₄-C₁₀ alkylA is independently B, D or EB is —CO₂H— acid side chainD is —CO—X-QE is —COO⁻Y⁺— Neutralised salt.X is O⁻ or NH—Q is —(CHR₃—CH₂O)_(n)—R₄R₃ is independently H, —CH₃ or —CH₂CH₃ or mixtures thereof (R₃ ispreferably H or —CH₃ or mixtures thereof, more preferably R₃ is H)n is 3-45, especially 3-30R₄ is a C₁-C₂₅, especially C₁-C₁₈, more especially C₁-C₈ alkylY is an alkali metal, an alkaline earth metal or an ammonium saltderived from ammonia or an amine or alkanolamine or mixtures thereof.

j, k and l are the average number of repeating units within the graftcopolymer.

j must be greater than 2 and desirably 3 or more.

k can be 0 when l=1 or greater than 1, or k can be 1 or greater than 1.

l can be 0 when k=1 or greater than 1, or l can be 1 or greater than 1.

The sum of j, k and l are such that the polymer has a molecular weightof between 1000 to 100,000.

In one embodiment, the ratio of j to k is 7:3 and l=0.

In one embodiment, the ratio of j to l is 1:1 and k=0.

The ratio of B to D to E is as follows:

B can be from 45 to 84.5%

D can be from 15 to 40%

E can be from 0.5 to 15%

As used herein the percentage ranges or ratios shown for B, D, E and Fare on a mole percent basis.

Y⁺ may independently be a metal cation (typically an alkali metalcation, an alkaline earth metal cation), or an ammonium cation(typically derived from ammonia or an amine such as an alkanolamine).

R₃ may be a mixture of —H and —CH₃, and typically with a ratio of —H to—CH₃ of no less than 75 mol % —H: 25 mol % —CH₃. In one embodiment R₃may be a mixture of —H and —CH₃, and the ratio of —H to —CH₃ 85 mol %—H: 15 mol % —CH₃

In one embodiment, the invention provides a composition comprising aparticulate solid (typically a pigment or filler), an organic medium(typically the organic medium may be a plastics material or an organicliquid) and a polyacrylic-acid containing copolymer comprising repeatunits j+k, j+l or j+k+l whereby the copolymer must comprise j and haveat least one repeat unit where A=B, at least one repeat unit where A=Dand at least one repeat unit where A=E as described above.

In one embodiment, the invention provides a composition comprising aparticulate solid, an organic medium and polyacrylic-acid containingcopolymer comprising repeat units j+k, j+l or j+k+l whereby thecopolymer must comprise j and have at least one repeat unit where A=B,at least one repeat unit where A=D and at least one repeat unit whereA=E as described above.

In one embodiment, the invention provides for the use of thepolyacrylic-acid containing copolymer comprising repeat units j+k, j+lor j+k+l whereby the copolymer must comprise j and have at least onerepeat unit where A=B, at least one repeat unit where A=D and at leastone repeat unit where A=E as described above as a dispersant, typicallya particulate dispersant in a plastic material.

In one embodiment, the invention provides for the use of thepolyacrylic-acid containing copolymer comprising repeat units j+k, j+lor j+k+l whereby the copolymer must comprise j and have at least onerepeat unit where A=B, at least one repeat unit where A=D and at leastone repeat unit where A=E as described above as a dispersant in thecomposition disclosed herein.

In some instances, a small amount of side reaction may occur when tworepeat units next to each other both have A=B.

In this instance, two acid groups can combine to form an anhydride,thus:

where A is defined above.

In one embodiment, from 0% to 10% of B can form anhydride groups in thismanner.

In one embodiment, from 0% to 1% of B can form anhydride groups in thismanner.

In one embodiment, when X is N—H, one B group can react with one D groupto form an imide thus:

where A and Q are defined as above.

In one embodiment, from 0% to 100% of D groups can form imide groupswhen combined with a B group in this manner.

In one embodiment, the copolymer may contain up to 10% of a monomerselected from 2-acrylamido-2-methylpropane sulfonic acid, vinyl toluene,styrene, alkyl(meth)acrylates and mixtures thereof.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a composition as disclosed herein above.

As used herein, the term “(meth)acryl” means acrylic or methacrylicunits.

The polyacrylic acid-containing graft copolymer (dispersant) of theinvention may have up to 10% of any of the repeat units j, k, and lreplaced by a repeat unit selected from styrene, vinyl toluene, analkyl(meth)acrylate, 2-acrylamido-2-methylpropane sulphonic acid, andmixtures thereof.

The alkyl(meth)acrylate may be methyl (meth)acrylate, butylmethacrylate, 2-methylpentyl(meth)acrylate,2-propylheptyl(meth)acrylate, 2-butyloctyl(meth)acrylate,2-ethylhexyl(meth)acrylate, octyl(meth)acrylate, nonyl(meth)acrylate,isooctyl(meth)acrylate, isononyl(meth)acrylate,2-tert-butylheptyl(meth)acrylate, 3-isopropylheptyl(meth)acrylate,decyl(meth)acrylate, undecyl(meth)acrylate,5-methylundecyl(meth)acrylate, dodecyl(meth)acrylate,2-methyldodecyl(meth)acrylate, tridecyl(meth)-acrylate,5-methyltridecyl(meth)acrylate, tetradecyl(meth)acrylate,pentadecyl(meth)acrylate, hexadecyl(meth)acrylate,2-methylhexadecyl(meth)acrylate, heptadecyl(meth)acrylate,octadecyl(meth)acrylate, nonadecyl(meth)acrylate, eicosyl(meth)acrylate,or mixtures thereof.

The (poly)acrylic copolymer of the invention may have a number averagemolecular weight in the range of 1000 to 100,000, or 1000 to 50,000.

In one embodiment, each R₁ may independently be hydrogen, X mayindependently be —O—, Q may independently be —(CHR₃—CH₂O)_(m)R₄, R₃ mayindependently be —H or —CH₃, R₄ may independently be a hydrocarbyl grouptypically containing 1 to 8 carbon atoms, and Y⁺ may independently be anammonium cation.

In one embodiment, each R₁ may independently be hydrogen, X mayindependently be —NH—, Q may independently be —(CHR₃—CH₂O)_(m)R₄, R₃ mayindependently be —H or —CH₃, R₄ may independently be a hydrocarbyl grouptypically containing 1 to 8 carbon atoms, and Y⁺ may independently be anammonium cation.

In one embodiment, each R₁ may independently be hydrogen, X mayindependently be —O—, Q may independently be —(CHR₃—CH₂O)_(m)R₄, R₃ maybe —H, R₄ may independently be a hydrocarbyl group containing 1 to 8carbon atoms, and Y⁺ may independently be an ammonium cation.

In one embodiment, each R₁ may independently be hydrogen, X mayindependently be —NH—, Q may independently be —(CHR₃—CH₂O)_(m)R₄, R₃ maybe —H, R₄ may independently be a hydrocarbyl group containing 1 to 8carbon atoms, and Y⁺ may independently be an ammonium cation.

R₂ may independently be H or a C₁₋₁₆ alkyl group and preferably C₄₋₁₀alkyl.

Examples of the monomers that may be used for the repeat unit k include,vinyl monomers such as ethene, propene, isobutylene, 1-hexene,1-heptene, 1-octene, 2-methyl-1-heptene, 4-methyl-1-pentene, 1-nonene,1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene.

R₄ may be alkyl, aryl or alkaryl groups. The alkyl groups may be linear,branched or cyclic.

R₄ may, for instance, be methyl, ethyl, propyl, iso-propyl, n-butyl,i-butyl, t-butyl, pentyl, hexyl, heptyl, octyl, 2-ethyhexyl, nonyl,decyl, dodecyl, 2-methyldodecyl, tridecyl, 5-methyltridecyl, tetradecyl,pentadecyl, hexadecyl, 2-methylhexadecyl, heptadecyl, octadecyl,nonadecyl, eicosyl, or mixtures thereof.

When X is —O—, the X-Q group may be derived from a polyalkylene glycolmono-substituted alkylether, or mixtures thereof. The polyalkyleneglycol mono-substituted alkylether may be a homopolymer or random orblock copolymer, typically containing ethylene glycol. Typically, if X-Qcontains a propylene glycol substituent, it is present as a random orblock copolymer with ethylene glycol.

For example, the X-Q group may be derived from methoxy polyethyleneglycol, ethoxy polyethylene glycol, propoxy polyethylene glycol, butoxypolyethylene glycol, methoxy polypropylene glycol, ethoxy polypropyleneglycol, propoxy polypropylene glycol, or butoxy polypropylene glycol.

When X is —NH—, the X-Q group may be derived from a polyalkyleneoxidemonoalkyl ether monoamine. The monoamine compounds of this type arecommercially available as the Surfonamine® amines from HuntsmanCorporation. Specific examples of Surfonamine® amines are B-60(propylene oxide to ethylene oxide mole ratio of 9:1), L-100 (propyleneoxide to ethylene oxide mole ratio of 3:19), B-200 (propylene oxide toethylene oxide mole ratio of 29:6) and L-207 (propylene oxide toethylene oxide mole ratio of 10:32), L200 (propylene oxide to ethyleneoxide mole ratio of 3:41), L-300 (propylene oxide to ethylene oxide moleratio of 8:58).

Y⁺ may independently be a metal cation (typically an alkali metalcation, an alkaline earth metal cation), or an ammonium cation(typically derived from ammonia or an amine or an alkanolamine).

The metal cation may be lithium, sodium or potassium, magnesium,calcium, barium or mixtures thereof.

In one embodiment, Y⁺ may independently be an ammonium cation. Theammonium cation may be derived from ammonia, a linear, or branchedaliphatic amine, a cyclic amine, an aromatic amine, or aminoalcohol. Inone embodiment, the aminoalcohol may be linear.

Examples of an amine that may be used to generate the ammonium cationinclude trimethylamine, triethylamine, tributylamine, aminoalkylsubstituted heterocyclic compounds (such as 1-(3-aminopropyl)imidazole,4-(3-aminopropyl)morpholine, 1-(2-aminoethyl)piperidine,3,3-diamino-N-methyldipropylamine,3,3′-aminobis(N,N-dimethylpropylamine), N,N-dimethyl-aminopropylamine,N,N-diethyl-aminopropylamine, N,N-dimethyl-aminoethylamine, morpholine,or mixtures thereof.

When Y⁺ is an ammonium from an amine, the amine may be polyalkyleneoxidemonoalkyl ether monoamine as described above.

When Y⁺ is from an aminoalcohol, Y+ may be the residue of anaminoalcohol such as ethanolamine, isopropanolamine, diethanolamine,triethanolamine, diethylethanolamine, dimethylethanolamine,dibutylethanolamine, 3-amino-1,2-propanediol; serinol;2-amino-2-methyl-1,3-propanediol; tris(hydroxymethyl)-aminomethane;1-amino-1-deoxy-D-sorbitol; diisopropanolamine;N-methyl-N,N-diethanolamine;N,N,N′,N′-tetrakis(2-hydroxypropyl)ethylenediamine,2-amino-2-methyl-1-propanol, 2-dimethylamino-methyl-1-propanediol,2-amino-2-ethyl-1,3-propanediol, 2-amino-1-butanol, or mixtures thereof.

The polyacrylic-acid containing graft copolymer may be prepared byprocesses known to a skilled person. For example, the polyacrylic-acidcontaining copolymer may be prepared by esterification or amidation ofpoly(meth)acrylic acid, or polymerisation of (meth)acrylic acid with(meth)acrylic esters and/or amides by any known polymerization techniqueor a combination of polymerization techniques using a bulk, solution,suspension or emulsion process. The polymerization may comprise of aradical, anionic, cationic, atom transfer or group transferpolymerization process or combinations thereof.

In one embodiment, the invention further provides for a compositioncomprising particulate solid (typically a pigment or filler), an organicmedium (typically the organic medium may be a plastics material or anorganic liquid) and a polyacrylic-acid containing copolymer comprisingrepeat units j+k, j+l or j+k+l whereby the copolymer must comprise j andhave at least one repeat unit where A=B, at least one repeat unit whereA=D and at least one repeat unit where A=E as described above.

In different embodiments, the invention provides a polyacrylic copolymerfurther having 0 mol % to 2 mol %, or 0 mol % to 1 mol %, or 0 mol % ofan anhydride group.

In one embodiment, the invention provides for a compoundobtained/obtainable by reacting poly(meth)acrylic acid (typically with amolecular weight between 300 and 90,000, or 300 and 45,000), either asan aqueous solution or a solid, and Q-X—H, as defined herein, in theratio of between 5 and 95 parts by weight, to 95 parts and 5 parts byweight, in the presence of a catalyst, typically an acid catalyst, at atemperature between 120 and 200 Celsius, under an inert atmosphere, fora duration of between 2 hours and 72 hours, ensuring that water presentin the reaction or generated during the reaction is removed. Thisgenerates an intermediate which is subsequently reacted with Y⁺—H, whereY⁺ is defined herein, in the ratio of from 1 part intermediate to 1 partY⁺—H by weight to 1 part intermediate to 0.00001 part Y⁺—H, at atemperature between 50 and 100 Celsius, for a duration of between 0.5 to24 hours, under an inert atmosphere in the absence of water.

In one embodiment, the invention provides for a polymerobtained/obtainable by a process comprising:

(i) reacting poly(meth)acrylic acid, either as an aqueous solution or asolid (typically having a molecular weight between 300 and 90000, or 300and 45000), with an alcohol or amine, whilst simultaneously removingwater from the reaction (for instance by distillation or othertechniques known to a person skilled in the art); Where A=D, the CO₂—X-Qgroup above may be derived from the amine or alcohol. Typically thepoly(meth)acrylic acid to alcohol or amine ratio may be 5 and 95 partsby weight, to 65 parts and 35 parts by weight;

(ii) reacting the product of step (i) with a compound capable ofdelivering a metal cation or ammonium salt (as described for Y⁺ above)The mole ratio of the product of step (i) to the compound capable ofdelivering a metal cation or ammonium salt may range from 1 partsproduct of step (i) to 0.00001 parts of the compound capable ofdelivering a metal cation or ammonium salt, or 2 parts product of step(i) to 0.5 parts of the compound capable of delivering a metal cation orammonium salt. A person skilled in the art will appreciate that wheremolecular weight of A where A=D, is very high there would be a lownumber of free acid groups available per unit weight of the totalpolymer. If a neutralizing species with a low molecular weight were usedit would not require a large amount by weight to completely neutralizethe acid groups. As a result of this the mole ratio of the product ofstep (i) to the compound capable of delivering a metal cation orammonium salt may be as low as 1 parts product of step (i) to 0.00001parts of the compound capable of delivering a metal cation or ammoniumsalt.

Step (i) above may be performed in the presence or absence of acatalyst, (typically in the presence of an acid catalyst). The reactiontemperature of step (i) may also range from 120° C. to 200° C. Thereaction described in step (i) may be under an inert atmosphere. Step(i) may be performed for a duration of between 2 hours and 72 hours.

Step (ii) may be carried out at an elevated temperature ranging from 50°C. to 100° C. Step (ii) may be performed for a period of time rangingfrom 0.5 to 24 hours. Step (ii) may be performed in an inert or airatmosphere. In one embodiment, step (ii) may be carried out under aninert atmosphere and substantially free of water to free of water(typically free of water).

As used herein, the expression substantially free of water indicatesthat the reaction contains a minimal amount of water, for instance,contaminant or trace amounts not removed in step (i) of the processdescribed above.

The product of step (ii) may have a weight average molecular weight of1000 to 100,000, or 1000 to 50,000.

In one embodiment, the invention further provides for a compositioncomprising particulate solid (typically a pigment or filler), an organicmedium (typically the organic medium may be a plastics material or anorganic liquid) and a polyacrylic copolymer described by the product byprocess described above. The polyacrylic copolymer may be useful as adispersant in the composition described herein.

The particulate solid (typically a pigment or filler) may have anaverage particle size by measured by light scattering measurements offrom 10 nanometers to 10 microns, or 10 nanometers to 1, 2, 3, or 5microns, or 20 nanometers to 1, 2, 3, or 5 microns in diameter.

INDUSTRIAL APPLICATION

In one embodiment, the polyacrylic copolymer disclosed herein is adispersant, typically used for dispersing particulate solid materials.

The polyacrylic copolymer disclosed herein, in different embodiments, ispresent in the composition of the invention in a range selected from 0.1to 50 w. %, or 0.25 to 35 wt. %, and 0.5 to 30 wt. %.

The particulate solid present in the composition may be any inorganic ororganic solid material which is substantially insoluble in the organicmedium at the temperature concerned and which it is desired to stabilizein a finely divided form therein. The particulate solids may be in theform of a granular material, a fibre, a platelet or in the form of apowder, often a blown powder. In one embodiment, the particulate solidis a filler.

Examples of suitable solids are pigments, extenders, fillers, blowingagents and flame retardants for plastics materials; dyes, especiallydisperse dyes; metals; particulate ceramic materials and magneticmaterials for ceramics, piezoceramic printing, abrasives, capacitors, orfuel cells, ferrofluids; organic and inorganic nanodisperse solids;fibres such as wood, paper, glass, steel, or carbon and boron forcomposite materials.

Examples of inorganic pigments include metallic oxides, such as titaniumdioxide, rutile titanium dioxide and surface coated titanium dioxide,titanium oxides of different colours such as yellow and black, ironoxides of different colours such as yellow, red, brown and black, zincoxide, zirconium oxides, aluminium oxide, oxymetallic compounds, such asbismuth vanadate, cobalt aluminate, cobalt stannate, cobalt zincate,zinc chromate and mixed metal oxides of two or more of manganese,nickel, titanium, chromium, antimony, magnesium, cobalt, iron oraluminium, Prussian blue, vermillion, ultramarine, zinc phosphate, zincsulphide, molybdates and chromates of calcium and zinc, metal effectpigments, such as aluminium flake, copper, and copper/zinc alloy,pearlescent flake such as lead carbonate and bismuth oxychloride.

Inorganic solids include extenders and fillers such as ground andprecipitated calcium carbonate, calcium sulphate, calcium oxide, calciumoxalate, calcium phosphate, calcium phosphonate, barium sulphate, bariumcarbonate, magnesium oxide, magnesium hydroxide, natural magnesiumhydroxide or brucite, precipitated magnesium hydroxide, magnesiumcarbonate, dolomite, aluminium trihydroxide, aluminium hydroperoxide orboehmite, calcium and magnesium silicates, aluminosilicates includingnanoclays, kaolin, montmorillonites including bentonites, hectorites andsaponites, mica, talc including muscovites, phlogopites, lepidolites andchlorites, chalk, synthetic and precipitated silica, fumed silica, metalfibres and powders, zinc, aluminium, glass fibres, refractory fibres,carbon black, including single- and multi-walled carbon nanotubes,reinforcing and non-reinforcing carbon black, graphite,Buckminsterfullerenes, asphaltene, graphene, diamond, alumina, quartz,silica gel, wood flour, wood flake including soft and hard woods, sawdust, powdered paper/fibre, cellulosic fibres, such as kenaf, hemp,sisal, flax, cotton, cotton linters, jute, ramie, rice husk or hulls,raffia, typha reed, coconut fibre, coir, oil palm fibre, kapok, bananaleaf, caro, curaua, henequen leaf, harakeke leaf, abaca, sugar canebagasse, straw, bamboo strips, wheat flour, MDF and the like,vermiculite, zeolites, hydrotalcites, fly ash from power plants,incinerated sewage sludge ash, pozzolanes, blast furnace slag, asbestos,chrysotile, anthophylite, crocidolite, wollastonite, attapulgite and thelike, particulate ceramic materials such as alumina, zirconia, titania,ceria, silicon nitride, aluminium nitride, boron nitride, siliconcarbide, boron carbide, mixed silicon-aluminium nitrides and metaltitanates; particulate magnetic materials such as the magnetic oxides oftransition metals, often iron and chromium, e.g., gamma-Fe₂O₃, Fe₃O₄,and cobalt-doped iron oxides, ferrites, e.g., barium ferrites; and metalparticles, for instance, metallic aluminium, iron, nickel, cobalt,copper, silver, gold, palladium, and platinum and alloys thereof.

Other useful solid materials include flame retardants such aspentabromodiphenyl ether, octabromodiphenyl ether, decabromodiphenylether, hexabromocyclododecane, ammonium polyphosphate, melamine,melamine cyanurate, antimony oxide and borates.

The organic medium present in the composition of the invention in oneembodiment is a plastics material and in another embodiment an organicliquid. The organic liquid may be a non-polar or a polar organic liquid,although a polar organic liquid is typically used. By the term “polar”in relation to the organic liquid, it is meant that an organic liquid iscapable of forming moderate to strong bonds as described in the articleentitled “A Three Dimensional Approach to Solubility” by Crowley et al.in the Journal of Paint Technology, Vol. 38, 1966, at page 269. Suchorganic liquids, generally, have a hydrogen bonding number of 5 or moreas defined in the abovementioned article.

Examples of suitable polar organic liquids are amines, ethers,especially lower alkyl ethers, organic acids, esters, ketones, glycols,alcohols and amides. Numerous specific examples of such moderatelystrongly hydrogen bonding liquids are given in the book entitled“Compatibility and Solubility” by Ibert Mellan (published in 1968 byNoyes Development Corporation) in Table 2.14 on pages 39-40, and theseliquids all fall within the scope of the term polar organic liquid, asused herein.

In one embodiment, polar organic liquids include dialkyl ketones, alkylesters of alkane carboxylic acids and alkanols, especially such liquidscontaining up to, and including, a total of 6 or 8 carbon atoms. Asexamples of the polar organic liquids include dialkyl and cycloalkylketones, such as acetone, methyl ethyl ketone, diethyl ketone,di-isopropyl ketone, methyl isobutyl ketone, di-isobutyl ketone, methylisoamyl ketone, methyl n-amyl ketone and cyclohexanone; alkyl esterssuch as methyl acetate, ethyl acetate, isopropyl acetate, butyl acetate,ethyl formate, methyl propionate, methoxypropyl acetate and ethylbutyrate; glycols and glycol esters and ethers, such as ethylene glycol,2-ethoxyethanol, 3-methoxypropylpropanol, 3-ethoxypropylpropanol,2-butoxyethyl acetate, 3-methoxypropyl acetate, 3-ethoxypropyl acetateand 2-ethoxyethyl acetate; alkanols such as methanol, ethanol,n-propanol, isopropanol, n-butanol and isobutanol and dialkyl and cyclicethers such as diethyl ether and tetrahydrofuran. In one embodiment,solvents are alkanols, alkane carboxylic acids and esters of alkanecarboxylic acids.

Examples of organic liquids which may be used as polar organic liquidsare film-forming resins. Examples of such resins include polyamides,such as Versamid™ and Wolfamid™, and cellulose ethers, such as ethylcellulose and ethyl hydroxyethyl cellulose, nitrocellulose and celluloseacetate butyrate resins, including mixtures thereof. Examples of resinsinclude short oil alkyd/melamine-formaldehyde,polyester/melamine-formaldehyde, thermosettingacrylic/melamine-formaldehyde, long oil alkyd, polyether polyols andmulti-media resins such as acrylic and urea/aldehyde.

The organic liquid may be a polyol, that is to say, an organic liquidwith two or more hydroxy groups. In one embodiment, polyols includealpha-omega diols or alpha-omega diol ethoxylates.

In one embodiment, non-polar organic liquids are compounds containingaliphatic groups, aromatic groups or mixtures thereof. The non-polarorganic liquids include non-halogenated aromatic hydrocarbons (e.g.,toluene and xylene), halogenated aromatic hydrocarbons (e.g.,chlorobenzene, dichlorobenzene, chlorotoluene), non-halogenatedaliphatic hydrocarbons (e.g., linear and branched aliphatic hydrocarbonscontaining six or more carbon atoms, both fully and partiallysaturated), halogenated aliphatic hydrocarbons (e.g., dichloromethane,carbon tetrachloride, chloroform, trichloroethane) and natural non-polarorganics (e.g., vegetable oil, sunflower oil, linseed oil, terpenes andglycerides).

In one embodiment, the organic liquid includes at least 0.1% by weight,or 1% by weight or more of a polar organic liquid based on the totalorganic liquid.

In one embodiment, the organic liquid is free of water.

The plastics material may be a thermosetting resin or a thermoplasticresin. The thermosetting resins useful in this invention include resins,which undergo a chemical reaction when heated, catalysed, or subject toultra-violet, laser light, infra-red, cationic, electron beam, ormicrowave radiation and become relatively infusible. Typical reactionsin thermosetting resins include oxidation of unsaturated double bonds,reactions involving epoxy/amine, epoxy/carbonyl, epoxy/hydroxyl,reaction of epoxy with a Lewis acid or Lewis base,polyisocyanate/hydroxy, amino resin/hydroxy moieties, free radicalreactions or polyacrylate, cationic polymerization of epoxy resins andvinyl ether and condensation of silanol. Examples of unsaturated resinsinclude polyester resins made by the reaction of one or more diacids oranhydrides with one or more diols. Such resins are commonly supplied asa mixture with a reactive monomer such as styrene or vinyltoluene andare often referred to as orthophthalic resins and isophthalic resins.Further examples include resins using dicyclopentadiene (DCPD) as aco-reactant in the polyester chain. Further examples also include thereaction products of bisphenol A diglycidyl ether with unsaturatedcarboxylic acids such as methacrylic acid, subsequently supplied as asolution in styrene, commonly referred to as vinyl ester resins.

Polymers with hydroxy functionality (frequently polyols) are widely usedin thermosetting systems to crosslink with amino resins orpolyisocyanates. The polyols include acrylic polyols, alkyd polyols,polyester polyols, polyether polyols and polyurethane polyols. Typicalamino resins include melamine formaldehyde resins, benzoguanamineformaldehyde resins, urea formaldehyde resins and glycolurilformaldehyde resins. Polyisocyanates are resins with two or moreisocyanate groups, including both monomeric aliphatic diisocyanates,monomeric aromatic diisocyanates and their polymers. Typical aliphaticdiisocyanates include hexamethylene diisocyanate, isophoronediisocyanate and hydrogenated diphenylmethane diisocyanate. Typicalaromatic isocyanates include toluene diisocyanates and diphenylmethanediisocyanates.

The plastics material such as a thermoset resin may be useful for partsin boat hulls, baths, shower trays, seats, conduits and bulkheads fortrains, trams, ships aircraft, body panels for automotive vehicles andtruck beds.

If desired, the compositions containing plastic material may containother ingredients, for example dispersants other than the compound ofthe present invention, antifogging agents, nucleators, blowing agents,flame retardants, process aids, surfactants, plasticisers, heatstabilizers, UV absorbers, anti-oxidants, fragrances, mould releaseaids, anti-static agents, anti-microbial agents, biocides, couplingagents, lubricants (external and internal), impact modifiers, slipagents, air release agents and viscosity depressants.

The compositions typically contain from 1 to 95% by weight of theparticulate solid, the precise quantity depending on the nature of thesolid and the quantity depending on the nature of the solid and therelative densities of the solid and the polar organic liquid. Forexample, a composition in which the solid is an organic material, suchas an organic pigment, in one embodiment contains from 15 to 60% byweight of the solid whereas a composition in which the solid is aninorganic material, such as an inorganic pigment, filler or extender, inone embodiment contains from 40 to 90% by weight of the solid based onthe total weight of composition.

The composition may be prepared by any of the conventional methods knownfor preparing dispersions. Thus, the solid, the organic medium and thedispersant may be mixed in any order, the mixture then being subjectedto a mechanical treatment to reduce the particles of the solid to anappropriate size, for example, by ball milling, bead milling, gravelmilling, high shear mixing or plastic milling until the dispersion isformed. Alternatively, the solid may be treated to reduce its particlesize independently or in admixture with either, the organic medium orthe dispersant, the other ingredient or ingredients then being added andthe mixture being agitated to provide the composition.

In one embodiment, the composition of the present invention is suited toliquid dispersions. In one embodiment, such dispersion compositionscomprise: (a) 0.5 to 40 parts of a particulate solid, (b) 0.5 to 30parts of a polyacrylic-acid-containing copolymer disclosed herein, and(c) 30 to 99 parts of an organic medium; wherein all parts are by weightand the amounts (a)+(b)+(c)=100.

In one embodiment, component a) includes 0.5 to 40 parts of a pigmentand such dispersions are useful as mill-bases.

If a composition is required, including a particulate solid and apolyacrylic-acid-containing copolymer disclosed herein in dry form, theorganic liquid is typically volatile so that it may be readily removedfrom the particulate solid by a simple separation means such asevaporation. In one embodiment, the composition includes the organicliquid.

If the dry composition consists essentially of thepolyacrylic-acid-containing copolymer disclosed herein and theparticulate solid, it typically contains at least 0.2%, at least 0.5% orat least 1.0% the polyacrylic-acid-containing copolymer disclosed hereinbased on weight of the particulate solid. In one embodiment, the drycomposition contains not greater than 100%, not greater than 50%, notgreater than 20%, or not greater than 10% by weight of thepolyacrylic-acid-containing copolymer disclosed herein based on theweight of the particulate solid. In one embodiment, thepolyacrylic-acid-containing copolymer disclosed herein is present at 0.6wt. % to 8 wt. %.

As disclosed hereinbefore, the compositions of the invention aresuitable for preparing mill-bases wherein the particulate solid ismilled in an organic liquid in the presence of apolyacrylic-acid-containing copolymer disclosed herein, or saltsthereof.

Thus, according to a still further embodiment of the invention, there isprovided a mill-base including a particulate solid, an organic liquidand polyacrylic-acid-containing copolymer disclosed herein, or saltsthereof.

Typically, the mill-base contains from 20 to 70% by weight particulatesolid based on the total weight of the mill-base. In one embodiment, theparticulate solid is not less than 10 or not less than 20% by weight ofthe mill-base. Such mill-bases may optionally contain a binder, addedeither before or after milling. The binder is a polymeric materialcapable of binding the composition on volatilisation of the organicliquid.

Binders are polymeric materials including natural and syntheticmaterials. In one embodiment, binders include poly(meth)acrylates,polystyrenics, polyesters, polyurethanes, alkyds, polysaccharides suchas cellulose, and natural proteins such as casein. In one embodiment,the binder is present in the composition at more than 100% based on theamount of particulate solid, more than 200%, more than 300% or more than400%.

The amount of optional binder in the mill-base can vary over wide limitsbut is typically not less than 10%, and often not less than 20% byweight of the continuous/liquid phase of the mill-base. In oneembodiment, the amount of binder is not greater than 50% or not greaterthan 40% by weight of the continuous/liquid phase of the mill-base.

The amount of dispersant in the mill-base is dependent on the amount ofparticulate solid but is typically from 0.5 to 5% by weight of themill-base.

Dispersions and mill-bases made from the composition of the inventionare particularly suitable for use in non-aqueous and solvent freeformulations in which energy curable systems (ultra-violet, laser light,infra-red, cationic, electron beam, microwave) are employed withmonomers, oligomers, etc., or a combination present in the formulation.They are particularly suitable for use in plastics; polyol and plastisoldispersions; non-aqueous ceramic processes, especially tape-casting,gel-casting, doctor-blade, extrusion and injection moulding typeprocesses, a further example would be in the preparation of dry ceramicpowders for isostatic pressing; composites such as sheet moulding andbulk moulding compounds, resin transfer moulding, pultrusion,hand-lay-up and spray-lay-up processes, matched die moulding;construction materials like casting resins, and plastics materials. Theyare useful in the surface modification of pigments and fillers toimprove the dispersibility of dry powders used in the aboveapplications. Further examples of coating materials are given in BodoMuller, Ulrich Poth, Lackformulierung und Lackrezeptur, Lehrbuch frAusbildung und Praxis, Vincentz Verlag, Hanover (2003) and in P. G.Garrat, Strahlenhartung, Vincentz Verlag, Hanover (1996). Examples ofprinting ink formulations are given in E. W. Flick, Printing Ink andOverprint Varnish Formulations—Recent Developments, Noyes Publications,Park Ridge N.J., (1990) and subsequent editions.

In one embodiment, the composition of the invention further includes oneor more additional known dispersants.

The following examples provide illustrations of the invention. Theseexamples are non exhaustive and are not intended to limit the scope ofthe invention. All chemicals were purchased from Aldrich except wherestated.

EXAMPLES

Comparative Example A (COMA) is a compound made by the process describedin GB 887 241, Example 1.

Intermediate 1

Poly(acrylic-co-maleic acid) (1:1 mole ratio, MW 3000, Ex Sigma Aldrich,50% active in water, 45.7 parts) and polyethyleneglycol monomethyl ether(MW 500, Ex Ineos, 60.77 parts) and Orthophosphoric acid (Ex SigmaAldrich, 0.25 parts) are charged to a reaction flask and heated, under anitrogen blanket to 150° C. and stirring maintained for 23 hours, givinga Clear orange liquid.

Intermediate 2

Poly(acrylic-co-maleic acid) (1:1 mole ratio, MW 3000, Ex Sigma Aldrich,50% active in water, 17.74 parts) and Surfonamine® L-100 ether (ExHuntsman, 47.18 parts) and Orthophosphoric acid (Ex Sigma Aldrich, 0.17parts) are charged to a reaction flask and heated, under a nitrogenblanket to 150° C. and stirring maintained for 22 hours, giving anorange solid.

Intermediate 3

Poly(acrylic acid-co-dodecene) (7:3 mole ratio, MW 1920, Ex Lubrizol,19.28 parts) and polyethyleneglycol monomethyl ether (MW 500, Ex Ineos,28.65 parts) are charged to a reaction flask and heated, under anitrogen blanket to 120° C. until homogeneous. Orthophosphoric acid (ExSigma Aldrich, 0.14 parts) is added. The reaction temperature isincreased to 180° C. and stirring maintained for 22 hours, giving aclear yellow liquid.

Preparative Example 1 (EX 1)

Intermediate 1 (32.1 parts) and triethanolamine (Ex Sigma Aldrich, 1.5parts) is charged to a reaction flask and heated to 70° C. under anitrogen blanket. Left to stir for 2 hours, giving a viscous clear brownliquid. This is dispersant 1.

Preparative Example 2 (EX 2)

Intermediate 2 (32.6 parts) and triethanolamine (Ex Sigma Aldrich, 0.87parts) is charged to a reaction flask and heated to 70° C. under anitrogen blanket. Left to stir for 2 hours, giving a brown solid. Thisis dispersant 2.

Preparative Example 3 (EX 3)

Intermediate 3 (17.31 parts) and triethanolamine (Ex Sigma Aldrich, 0.52parts) is charged to a reaction flask and heated to 70° C. under anitrogen blanket. Left to stir for 2 hours, giving a viscous clearyellow liquid. This is dispersant 3.

Dispersion Evaluation

All of the examples which are not already 50% active are diluted to 50%by the addition of a 1:1 mixture of Dowanol PM and Dowanol PMA.

Crystic 471 (unsaturated polyester resin (Ex Scott Bader Co, 50 g) andeach example dispersant (1 part active dispersant) is charged to astainless steel mill-pot and set to stir briskly for two minutes.Carbital 110 (calcium carbonate, ex Imerys Performance Minerals, 100parts) filler is added gradually until substantially all of the filleris charged. The mixture is then stirred at 3000 rpm for 15 minutes toform a paste. The paste is evaluated for viscosity.

Each paste sample is measured on a TA Instruments AR2000 ControlledStress rheometer in flow measurement mode, using a 40 mm stainless steelcross-hatched plate with a 1 mm gap. The experiment is a stepped-flowmeasurement at 25° C. The samples are sheared at rates of 0.2 s⁻¹ to 160s⁻¹. The viscosity data (Pas) obtained is as follows

Set 1 Shear Rate Example Viscosity PaS (1/s) Control COM EX1 EX2 EX30.2811 266.4 30.93 43.29 24.14 37.52 0.4999 376.8 27.29 30.83 20.6528.66 0.8889 565.8 24.11 23.38 17.78 22.88 1.581 709.6 22.44 19.31 16.1119.73 2.811 746.8 22.62 17.81 15.98 19.05 4.999 691.9 24.79 18.51 17.7220.94 8.889 481.5 27.89 21.2 21.51 24.8 15.81 312.1 29.54 22.6 23.9527.75 28.11 196.5 29.97 21.62 20.75 27.88 49.99 35.12 30.08 19.05 17.4629.2 88.89 3.327 22.5 14.52 13.84 15.42 Footnotes: Control does notcontain a dispersant.Typically, an additive which has superior performance over comparativeexamples, displays a lower viscosity for the majority of data pointsover the equivalent data points for the comparative example.Curing Data:

All of the examples, which are not already 50% active, are diluted to50% by the addition of a 1:1 mixture of Dowanol PM and Dowanol PMA.

Crystic® 471 PALV unsaturated polyester resin (Ex Scott Bader Co) andthe example (0.175 parts active dispersant) are mixed thoroughly in aglass vial. A thermocouple probe is used to measure the temperature ofthe mixture. Once a stable temperature is obtained methylethylketoneperoxide (Ex Aldrich) is added (0.4 parts) and the contents of the vialmixed well. The temperature of the mixture is sampled once per minuteover a 60 minute period, providing a measure of the speed of onset ofcuring and a peak temperature exotherm. In general terms, the higher andsooner the peak exotherm occurs then the more efficient the curing is. Apeak exotherm, which is significantly lowered or delayed, is displayinginterference in the curing mechanism from the dispersant used. In theseresults, a candidate formulation is judged to be a PASS if the peakexotherm is greater than 50 Celsius and the peak exotherm occurs beforea 40 minute period has elapsed. If the candidate formulation has a peakexotherm less than 50 Celsius and/or the exotherm occurs after a 40minute period has elapsed, the candidate is judged as a FAIL.

The results for the examples are:

Set 1 Peak Exotherm Time to Peak Exotherm Result for each Agents (° C.)(minutes) candidate Control- 105 26 PASS no agent COM 76 32 PASS EX1 7231 PASS EX2 115 24 PASS EX3 90 31 PASS

The data obtained from the tests indicates that the compositions of theinvention have acceptable curing performance and form improveddispersions over the compositions containing a comparative exampledispersant.

Each of the documents, referred to above, is incorporated herein byreference. Except in the Examples, or where otherwise explicitlyindicated, all numerical quantities in this description specifyingamounts of materials, reaction conditions, molecular weights, number ofcarbon atoms, and the like, are to be understood as modified by the word“about.” Unless otherwise indicated, each chemical or composition,referred to herein, should be interpreted as being a commercial gradematerial which may contain the isomers, by-products, derivatives, andother such materials which are normally understood to be present in thecommercial grade. However, the amount of each chemical component ispresented exclusive of any solvent or diluent oil, which may becustomarily present in the commercial material, unless otherwiseindicated. It is to be understood that the upper and lower amount,range, and ratio limits set forth herein may be independently combined.Similarly, the ranges and amounts for each element of the invention maybe used together with ranges or amounts for any of the other elements.

While the invention has been explained in relation to its preferredembodiments, it is to be understood that various modifications thereofwill become apparent to those skilled in the art upon reading thespecification. Therefore, it is to be understood that the inventiondisclosed herein is intended to cover such modifications as fall withinthe scope of the appended claims.

What is claimed is:
 1. A composition comprising particulate solidselected from a pigment or a filler, an organic medium selected from aplastics material or an organic liquid and a polyacrylic-acid-containingcopolymer comprising the general formula;—[CH₂—C(A)(R₁)]_(j)—[CH₂—C(R₁)(R₂)]_(k)—[CH(A)-C(R₁)(A)]_(l)- wherein;R₁ is H or —CH₃; R₂ is H or a C₁-C₁₆ alkyl; A is independently B, D orE; B is —CO₂H; D is —CO—X-Q; E is —COO⁻Y⁺; j, k and l are the averagenumber of repeating units within the graft copolymer j must be greaterthan 2 k is 0 when l=1 or greater than 1, or k is 1 or greater than 1 lis 0 when k=1 or greater than 1, or l is 1 or greater than 1 X is O— orNH—; Q is —(CHR₃—CH₂O)_(n)—R₄; R₃ is independently H, —CH₃ or —CH₂CH₃ ora mixture thereof; n is 3-45 R₄ is C₁₋₂₅ alkyl; Y is an alkali metal, analkaline earth metal, an ammonium salt derived from ammonia, an amine,an alkanolamine or a mixture thereof, wherein thepolyacrylic-acid-containing copolymer comprises repeat units j+k, j+l orj+k+l whereby the copolymer must comprise j and have at least one repeatunit where A=B, at least one repeat unit A=D and at least one repeatunit where A=E.
 2. A composition as claimed in claim 1 wherein the ratioof j to k is 7:3 and l=0.
 3. A composition as claimed in claim 1 whereinthe ratio of j to l is 1:1 and k=0.
 4. A composition as claimed in claim1 wherein n is 3-30.
 5. A composition as claimed in claim 1 wherein R₄is C₁-C₁₈.
 6. A composition as claimed in claim 1 wherein R₄ is C₁-C₈.7. A composition as claimed in claim 1 wherein the ratio of B:D:E is asfollows: B is from 45 to 84.5%; D is from 15 to 40%; and, E is from 0.5to 15%.
 8. A composition as claimed in claim 1 wherein said polyacryliccopolymer has a number average molecular weight in the range of 1000 to100,000.
 9. A composition as claimed in claim 1 wherein said polyacryliccopolymer is present 0.25 wt % to 35 wt % of the composition.
 10. Acomposition as claimed in claim 1 wherein the organic medium is anorganic liquid or a plastic material.
 11. A composition as claimed inclaim 10 wherein said organic liquid comprises at least 0.1 wt % of apolar organic liquid based on the total organic liquid.
 12. Acomposition as claimed in claim 1 wherein said plastic material is athermoset resin.
 13. A composition as claimed in claim 1 wherein saidpolyacrylic copolymer is pigment dispersant in said plastic material.14. A composition as claimed in claim 1 wherein said polyacryliccopolymer has a number average molecular weight in the range of 1000 to50,000.
 15. A composition as claimed in claim 1 wherein said polyacryliccopolymer is present 0.5 wt % to 30 wt % of the composition.